DISM in 11.2.0.2 on Solaris 10

From: Hameed, Amir <Amir.Hameed_at_xerox.com>
Date: Tue, 19 Jul 2011 09:59:03 -0400
Message-ID: <304F58144267C5439E733532ABC9A3A11229A577_at_USA0300MS02.na.xerox.net>

I have a two-node Oracle RAC 11.2.0.2 environment running multiple databases on M3000 servers. Both servers are identical in configuration with the exception that server A has twice the amount of physical memory than server B (64GB versus 32GB). The following parameters are NOT set in the SPFILE and therefore, DISM should not be enabled:  

SGA_TARGET SGA_MAX_SIZE MEMORY_MAX_TARGET MEMORY_TARGET   However, when I run the "ps" command at the OS, I observe the following:  

Node A:

ps -ef|grep svt2d1|grep dism

    root 13751 1 0 21:42:51 ? 0:00 ora_dism_svt2d101

    root 13762 1 0 21:42:53 ? 0:00 ora_dism_svt2d101

    root 13740 1 0 21:42:38 ? 0:00 ora_dism_svt2d101

    root 13745 1 0 21:42:49 ? 0:00 ora_dism_svt2d101  

Node B:

ps -ef|grep svt2d1|grep dism

    root 7517 1 0 21:42:33 ? 0:00 ora_dism_svt2d102

    root 7523 1 0 21:42:42 ? 0:00 ora_dism_svt2d102  

So, node A has twice the number of DISM processes running than node B. Based on my past experience with DISM with the previous Oracle database versions, I have seen only one DISM process running per instance and even in those situations, if the INIT parameters that impact DISM are turned off, no DISM process was found running.    

In the above RAC environment, when I run the "pmap" command, I see that the shared memory segment is using ISM as shown below:

ps -ef|grep svt2d|grep pmon

  oracle 13653 1 0 21:42:08 ? 0:13 ora_pmon_svt2d101  

pmap -xs 13653 | grep ism

0000000380000000 1261568 1261568 - 1261568 4M rwxsR [ ism shmid=0x7b00005f ]

00000003CD000000 8 8 - 8 8K rwxsR [ ism shmid=0x7b00005f ]  

So, based on the "pmap" command, it seems that DISM is turned OFF.  

To conclude, the following was observed in a two-node 11.2.0.2 RAC running on Solaris 10:

• With the database INIT parameters that enable DISM not set, DISM processes were found running on the server.
• There were more than one DISM processes running for each instance.
• Server with twice the amount of RAM had spawned twice the number of DISM processes than the one with half the amount of RAM.
• The "pmap" command showed that the instance was actually using ISM.

Has anyone made similar observations related to DISM in 11.2.0.2?  

Thanks

Amir  

--
http://www.freelists.org/webpage/oracle-l

Received on Tue Jul 19 2011 - 08:59:03 CDT